ESTRO 2025 - Abstract Book

S2731

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2025

Results: Achieved dosimetry based on 500 previous patient plans significantly outperforms the mandatory and recommended dose-volume limits for all threshold doses for bladder (table 1) and for all but the lowest dose level for rectum (table 2). The mean dose to the rectum was found to be 3Gy lower than the protocol limit for >99.9% of patients and 8Gy lower for >95% of patients. Performance-based data for the bladder shows that recommended volume limits are met in 99.95% of real-world cases. Volume limits for additional dose levels to those currently within the protocol could also be established for the bladder. Conclusion: The investigation demonstrates that current mandatory and desirable dosimetric constraints are set conservatively as upper safety limits rather than as achievable performance limits for the planning technique used. Adopting performance-based techniques would significantly reduce the acceptable volume-limit at most dose levels and lead to additional volume-limits for low-intermediate dose levels. Adopting performance based dose and dose-volume limits would improve patient safety by reducing the gap between the ceiling set for mandatory constraints and achievable dose distributions for >99.9% of patient plans.

Keywords: performance dose metrics, plan quality

References: 1. Caissie, Amanda et al. “Head and Neck Radiation Therapy Patterns of Practice Variability Identified as a Challenge to Real-World Big Data: Results From the Learning from Analysis of Multicentre Big Data Aggregation (LAMBDA) Consortium.” Advances in radiation oncology vol. 8,1 100925. 23 Feb. 2022, doi:10.1016/j.adro.2022.100925

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